Safety device for absorption refrigerating machines



July 12, 1927.

E NIEMANN SAFETY DEVICE FOR ABSORPT ION REFRIGERATING MACHINES Filed Dec. 10. 1924 IN V EN TOR.

[/Vz'emann I v ATTORNEYS.

1o monia and water.

w s July 12,1921.

u H'EE STATE EBIGH v E OF CHAJB-LOTTENBUBG-BEBLIN, GERMANY, ASSIGNQB 1'0 A.+G. Fll'R ELS-UND INDUBTBIEWERTE'GLARUS, OF GI IABUS, SWITZERLAND.

earns! DEVICE Ion. ansonr'rron nnrnresnarme macnmns.

Application filed December 10, 1924, Serial No. 755,034, and in Germany May 3, 1924.

5 grammatic illustrat on of the invention.

Figure 2 is a detail view of the safety de- V108.

The boiler K of an absor tion machine is provided with a fillin N, or example amis filling N heated during'the boiling period by the heating apparatus F, by means for example of petroleuqn gas or the like. The gases thus prodtced escape through the piping B in the generally known manner to the condenser,

separator and evaporator. After the close of the boiling period, cooling water is passed in the generally known manner from the main water supply pipe W through the water-regulating cock H,, by means of the pipe A, into the boiler,

coo -water supply and here flows throng the two cooling tubes R and R and is finally discharged through the water discharge ipe E.

Now in the case 0 the present invention a.

second water tube L (the tube for a fusible plug) is inserted for example in the upper cooling tube R for example by being screwed into a covering sleeve M. By

means of the separating sleeve V it is connected through the water cock H directly with the main cooling water pipe The free end of this pipe is supported in the cooling water tube R and has a smallbend at the end so that any jet of cooling water flowing out of this tube is directed straight against the wall of the tube R On to the endof the aforesaid water tube is screwed a fusible plug s, which is diagrammatically illustrated b itself in fuller detail in Figure 2. The fbsible plug (see Figure 2) consists of a simple iece of tubing T, carrying a screw thr at one end. The other end of this tube is filled with a metallic alloy, such as bismuth solder. This I 'alloy mustiiin each case be so selected that it fuses at a predetermined temperature.

Now the safety device works in the following manner 7 Let the boiling period of the boiler K be terminated for example upon a temperature of 118 C. and a working pressure of-eight atmospheres being reached. During the, boiling peried of course no cooling water has flowed through the tubes R and R,, as during this period only the condenser and the separator are cooled. If from any cause the heating fails to be discontinued, an unintentional continuance of the boiling will take place. Consequently the temperature and they pressure in the boiler must rise higher, and according to the quantity and nature of the filling the explosion danger zone will be reached for example at a temperature of 200 C. and a pressure of 35 atmospheres. Now the alloy of the fusible plug is so selected that it fuses at 130 C., that is to'say, long enough before the' explosion danger zone is reached. As soon as the alloy in the fusible plu begins to melt, the water tube L becomes Tree and accordingly an intensive jet of coolin water spurts vout of the tubeL, which is su jected to the tensively cooled down that not only is any further rise of temperature and pressure obviated but both are immediately reduced, that is to say, the temperature falls below 130 C. and the pressure drops sharply down.

at the same'time. In consequence of this coohng setting in, all danger of explosion -is completely obviated.

The advantages of this safety device in l comparison with the constructions hitherto.

known obviously rest on the fact-that the danger of explosion is obviated without any sort of mechanical apparatus being em- .ployed. The fusible plugmay be in "use for years without its melting point changing at all. B suitable choice of an alloy, such as bismut solder, the risk-is obviated of it being chemically changed, as for example'by being attacked by the refrigerating medium. A further advantage of this invention appears in the fact that when the plug comes into operation no sort of loss occurs of the boiler contents, that is to say, of the refrigcrating medium. A refilling or repairing by skilled workmen, or even returning the whole ap brains to the factory, is therefore saved. 6n the other hand anyone without previous experience would be able, sim ly by slackening the two sleercs V and from the tube L to unscrew the used fusible plugand insert a new! one. This operation is as simple for example as changing an ordinary electrical fuse in electrical plant of the usual nest of cooling tubes expressly constructed supplying a cooling medium to the other end for'this purpose. If there are-two or more boilers combined in one absorptionmachine theneach of these boilers is to be secured by the insertion of a safety device according to the invention.

WhatI claim is:' p

1. In an absorption refi'igerating apparatus a boiler having a cooling medium passage, a tube inserted in said passage and spaced therefrom, a fusible element .melting at a temperature exceeding the highest normal working-temperature of the apparatus and closing one end of saidtube, means :for

of said tube.

2. In an absorption refrigerating apparahis a. boiler having a cooling medium pas sage, a tube having at least one opening, said tube being inserted in said passage in a detachable way, a fusible element melting at a' predetermined temperature inserted in said ope g and closing it, means for supplying a cooling medium in said tube.

3. In an absorption refrigerating apparatils a boiler havmg a cooling medium passage, a tube inserted in said passage having 35 I at least one opening, a fusible element being inserted in said opening in a detachable way,

.one opening therein inclined to the walls of said passage, a fusible element closing said opening and melting at a "predetermined um pastemperature, means for supplying a cooling medium under pressure in said tube.

EBIGH 

